Give a known expense its own plan
A sinking fund is a pot of money for a cost you can see coming. Car registration, an insurance renewal, holiday gifts and an annual membership belong here. The goal is to spread a bill over the paychecks that arrive before it is due.
- Enter the total bill and the money already reserved for that bill.
- Choose the first payday on which you can set money aside, then the bill’s due date.
- Choose your pay schedule. Review the contribution before setting up a bank transfer.
The calculation
Remaining amount = bill − savings, with a minimum of zero. Payday contribution = remaining amount ÷ eligible paydays, rounded up to the nearest cent. A payday that lands on the due date is excluded to leave a small timing margin.
For example, a $600 bill with $120 already saved and 12 eligible paydays needs $40 each payday. If there are only three paydays, the same bill needs $160 per check. Dividing by twelve months would hide that catch-up problem.
Where this estimate stops
Employers sometimes move paydays for holidays. Monthly pay uses your starting day and clamps short months to their final day. Twice-monthly pay on fixed dates is not the same as every two weeks; count those paydays manually or use a weekly/monthly alternative only if it matches your real schedule. The tool does not move money or account for bank transfer delays.
Keep planning
Bill frequency calculator · Paycheck budget calculator · Shared bills calculator · Annual vs. monthly subscription · Emergency buffer calculator
Method reviewed November 1, 2026. Educational arithmetic; no individualized financial recommendations.